Sole Assembly for an Article of Footwear

ABSTRACT

The present invention is related to an article of footwear that has an upper extending around at least a portion of a foot. The outsole is secured to the upper. The article of footwear has a midsole that is detachably secured to the outsole. This midsole has a vertically projecting generally dome shaped support element located in the heel portion of the midsole. The dome shaped support element may be in contact with outsole interior sidewalls only while in an compressed state or it may remain in contact with the interior sidewalls in an uncompressed state. The dome shaped support element is at least partially covered by a cushioning cover that is made of a material less stiff than the material comprising the dome shaped support element. The cushioning cover may be partially covered by a heel plate that extends from the heel of the shoe towards the toe of the shoe. The heel plate may or may not extend the entire length of the shoe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 60/991,996, filed Dec. 3, 2007 and U.S. Provisional Patent Application No. 60/992,245, filed Dec. 4, 2007, which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to an article of footwear, and relates more specifically to a midsole assembly for an article of footwear.

BACKGROUND

Certain embodiments of the invention relate to an article of footwear such as a boot or shoe. Hereafter the term shoe will be used to refer to any article of footwear as part of which the below claimed invention can be used. Shoes are generally comprised of an outsole, a midsole, an insole, and an upper. The upper surrounds the foot or attaches the foot to the rest of the sole in the case of sandals. The upper may completely cover the foot or only a portion of it. The upper is often used to provide stability and ankle support. When an article of footwear is worn, the foot generally rests in the upper, on top of the insole. The insole is a thin layer on top of the midsole that typically provides some cushioning and support for the foot in the footbed. The midsole's primary function is to support the foot while the outsole is attached to the bottom, typically in order to provide traction. Some shoes do not have a formal midsole but have an outsole attached to the bottom of the shoe which may have cushioning and support mechanisms. A common goal of shoe design has been to provide a sole that provides both cushioning and stability to a shoe. In addition, the entire sole is preferably durable and resistant to wear and tear.

Traditionally non-athletic shoes worn for both casual events and more formal events have been made with bottoms composed of stiff materials such as leather and plastic. These materials are also used to form heels as part of the sole of the shoe. In some cases, heels are made of wood alone or some combination of the above materials. Leather, plastic, and wood are relatively rigid materials and provide little, if any, cushioning for the foot of the wearer. The use of such relatively rigid materials result in these types of shoes being uncomfortable for the wearer. The rigid materials may also cause pain in the feet, ankles, and knees of the wearer. Even during regular walking, there is a significant amount of force when the foot impacts the ground that can lead to pain without the appropriate shoe structure and cushioning. Walking in a stiff heel can cause additional stress on the wearer's legs and knees resulting in joint pain and soreness. Furthermore, when an individual stands, it is common to put his weight on his heels instead of evenly distributing his weight throughout the foot. This uneven distribution of weight over an extremely rigid surface can also result in ankle pain and lower back soreness.

Improved cushioning in these types of shoes, especially the heel region, could result in additional comfort to the wearer and reduce the physical stresses related to events which require significant amounts of time standing and walking. Such an improvement would also be beneficial in more casual settings which require significant amounts of walking or standing where hard or stiff soles may become uncomfortable over the course of the day.

Thus, there is a need for a comfortable sole assembly to be used in non-athletic shoes for both casual events and more sophisticated events that provides proper cushioning and support to the wearer's foot.

SUMMARY

The present invention is related to an article of footwear that has an upper extending around at least a portion of a foot. The outsole is secured to the upper. The article of footwear has a midsole that is detachably secured to the outsole. This midsole has a vertically projecting generally dome shaped support element located in the heel portion of the midsole. The dome shaped support element may be in contact with outsole interior sidewalls only while in an compressed state or it may remain in contact with the interior sidewalls in an uncompressed state. The dome shaped support element is at least partially covered by a cushioning cover that is made of a material less stiff than the material comprising the dome shaped support element. The cushioning cover may be partially covered by a heel plate that extends from the heel of the shoe towards the toe of the shoe. The heel plate may or may not extend the entire length of the shoe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a dome shaped support element according to certain embodiments of the invention.

FIG. 2 is a side view of the dome shaped support element according to certain embodiments of the invention.

FIG. 3 is an exploded side view of three of the components of the invention including the EVA cover, the dome shaped support element, and the outsole unit according to certain embodiments of the invention.

FIG. 4 is a bottom view of the dome shaped support element according to certain embodiments of the invention.

FIG. 5 is the side view of the assembled sole unit according to certain embodiments of the invention.

FIG. 6 is the bottom view of the assembled sole unit according to certain embodiments of the invention.

FIG. 7 is an exploded view of an assembled sole unit according to certain embodiments of the invention.

FIG. 8 is an exploded view of an assembled shoe unit according to certain embodiments of the invention.

DETAILED DESCRIPTION

Certain embodiments of the present invention solve the problems associated with traditional midsoles by providing a midsole with both support and cushioning in the heel region of the shoe. The shoe combines a dome shaped support element and support plate to provide stability and a less stiff cushioning cover over the dome shaped support element to enhance the cushioning and comfort of the shoe. FIGS. 1-8 depict the elements of certain embodiments of such a support and cushioning assembly as well as certain embodiments of complete shoe assemblies.

Certain embodiments of the invention provide an article of footwear with a viewing window in the outsole of the heel. The viewing window may be round in shape and made of a durable, transparent material such as a thermoplastic polyurethane, thermoplastic elastomer, or any other suitable material as known to those skilled in the art. The viewing window can be clear or tinted with any other color, preferably so as not to obstruct the ability to view the midsole through the viewing window. It is also not required that the viewing window be round, but can be of any shape that allows a dome shaped support element that rests above the window to be viewed through the outsole. It should be understood that certain embodiments of the invention may not require such a viewing window.

The viewing window in certain embodiments may be surrounded by the outsole which may be made of a durable material such as rubber. This material can be used for the length of the outsole or the outsole can be made of a combination of durable materials. The outsole can be a single layer or comprised of more than one layer of durable material such as rubber. The outsole can be of constant or varying thickness from the heel portion of the outsole to the toe portion.

In certain embodiments, the outsole portion of the shoe located in the heel portion of the sole has a generally disc shaped section removed from the outsole material. The removed section is above and adjacent to the viewing window but may be greater in diameter than the viewing window. This removed section extends vertically from the top of the viewing window to the top of the outsole portion of the heel leaving a cavity in the outsole material. This opening leaves a generally circular area for the dome shaped support element to be fitted into with a portion of the dome shaped support element in close proximity to or in contact with the outsole interior sidewalls. The outsole interior sidewalls extend approximately perpendicular to the length of the outsole which extends from the heel to the toe of the shoe assembly. The outsole interior sidewalls are created by the removed section of the outsole above the viewing window and are made of the same material as the outsole. The outsole interior sidewalls can also be created by molding the outsole to include them. The outsole interior sidewalls do not need to be generally circular but should be in a shape to accommodate the dome shaped support element.

The dome shaped support element in certain embodiments is made of a generally durable material such as Delrin® which is made by and trademarked by the E.I. DuPont de Nemours & Co. One form of Delrin® that may be used is an embodiment is Delrin 100STNC010®. Any material with similar characteristics could be substituted for this material.

The dome shaped support element in certain embodiments is generally circular at its base. The dome shaped support element extends from a wider base to the apex of the dome creating a shape that approximates half of a sphere. The base of the dome is located closer to the ground and outsole of the shoe while the apex is located near the heel of the wearer. The dome shaped support element in certain embodiments is not a continuous surface but is comprised of a variety of generally triangular shaped legs forming the dome. These legs are spaced evenly around the dome and project from the apex of the dome towards the base. Between the legs are spaces which create separation between the legs. In certain embodiments the separations between the legs project approximately ⅞ths of the way from the base of the dome towards the to the apex of the dome. The height of the separations from the base towards the apex may vary. The height of the dome shaped support element may vary based on the height of the heel of the shoe. Preferably the height of the dome is more than half of the height of the heel of the shoe. However, any height that is sufficient to provide the benefits of this advanced cushioning system is acceptable.

In certain embodiments, there may be feet at the base of the dome shaped support element legs that project radially outward from the center of the dome. These feet may be molded with the dome shaped support element and are used to fit the dome shaped support element into the generally circular portion of the outsole that has been removed and placed adjacent to the outsole interior sidewalls. In certain embodiments, these feet may be of a certain length to fit the dome shaped support element snuggly into the space touching the outsole interior sidewalls when in a relaxed state. They also may be of a shorter length allowing the feet to come in contact with the outsole interior side walls only when the dome shaped support element is compressed. The ability of the dome shaped support element to come into contact with the outsole interior sidewalls creates added stiffness to the heel dome structure which prevents over-compression of the dome shaped support element and potential heel collapse. The dome shaped support element may have any type of decorative inscription or grooves on it.

In certain embodiments, the dome shaped support element is fitted into the outsole with the feet of the dome shaped support element in close proximity to or contact with the outsole interior sidewalls. Upon the dome shaped support element being compressed, the heel dome feet come in contact with the outsole interior sidewalls. These sidewalls are a part of the outsole and comprised of the same stiff material. When the feet of the dome shaped support element come into contact with the outsole interior sidewalls, the dome shaped support element becomes more stiff to prevent over-compression of the heel of the article of footwear.

In certain embodiments, on top of the dome shaped support element is a cushioning cover which may be made of Ethylene Vinyl acetate (“EVA”), Thermoplastic Elastomer gel, or Polyurethene. Any other material that one of ordinary skill in the art would recognize to have similar properties could be substituted. Certain embodiments of the cushioning cover include a cover made of EVA that has a dome like shape which fits over the dome shaped support element and the feet of the dome shaped support element. The cushioning cover of certain embodiments is of a lesser thickness than the dome shaped support element.

Certain embodiments have a cushioning cover that is generally rectangular which may or may not have vents in the cushioning cover near the foot that extend over the dome shaped support element. These vents can take any form that one of ordinary skill in the art would know to use as vents. In certain embodiments, resting on and covering a portion of the cushioning cover is a heel plate. This heel plate may have an opening to allow the portions of the cushioning cover with vents to protrude through the heel plate towards the wearer's heel. This opening is not required and the heel plate may be one continuous plate. The heel plate is made of a durable and generally stiff material such as tuck board. The heel plate can be used to add firmness to the sole assembly mechanism. An insole may be placed on top of the heel plate for additional firmness or cushioning.

Referring now to the drawings, FIG. 1 depicts the upward projecting surface of the dome shaped support element according to certain embodiments of the present invention. The dome shaped support element can have a pattern inscribed on it or molded into it as depicted in FIG. 1 or a smooth texture on its top surface if desired. The dome is generally circular and has a number of legs 102 extending from an apex 101 of the dome shaped support element. The preferred shape of the legs is generally triangular as depicted, although other shapes may be appropriate. When placed into the heel portion of the shoe, the dome apex 101 projects towards the heel of the wearer and the legs 102 project downwards towards the outsole and the ground. The dome shaped support elements also have spaces 104 that extend between the legs 102 in certain embodiments of the invention. The height of the dome shaped support element is preferably determined based on the height of the heel of the shoe. The preferred height is typically more than half of the height of the heel of the shoe although any height that is sufficient to provide enhanced cushioning properties from traditional shoe soles is acceptable. Those skilled in the art may find it desirable to insert a formal midsole adjacent to the dome, which would influence the height of the dome.

FIG. 2 depicts a side view of the dome shaped support element with the apex 101 and legs 102. The legs may also have small feet 203 extending outwardly from the center of the dome 101. These feet 203 are used to position the dome shaped support element in the shoe and may expand the diameter of the dome shaped support element when the heel is compressed. Between the legs 102 are spaces 104. The spaces 104 allow the dome shaped support element to flex as needed to provide support and cushioning. In certain embodiments of the invention, the spaces 104 in the dome shaped support element extend generally at least half of the height of the dome shaped support element from the bottom of the heel towards the apex of the dome shaped support element.

FIG. 3 depicts the outsole and heel assembly from the side. The outsole unit 301 can be attached to an insole and upper to form a variety of shoe types including loafers, dress shoes, and boots. The forefoot and midfoot of the shoe 302 extends from the toes towards the heel region 304. The heel region 304 is where the dome shaped support element 305 is situated with the apex 101 projecting towards the wearer's heel when the shoe is in use and the legs 102 projecting downwards towards the ground. The dome shaped support element in certain embodiments has feet 203 which may be used to secure the dome shaped support element into the midsole. Those feet may come into contact with the interior sidewalls 306. The feet 203 may or may not be in contact with the interior sidewalls 306 when the shoe is not under compression. The viewing window 303 provides a viewing area into the heel region 304 to view the dome shaped support element. This window 303 can be a clear or shaded Thermoplastic Elastomer (“TPE”) or can be made from Thermoplastic Polyurethane. FIG. 4 depicts the bottom of the dome shaped support element. The dome shaped support element in FIG. 4 can have a pattern inscribed or molded into it as shown or can be smooth in texture. In addition, a logo or picture can be inscribed for viewing through the window 303.

In certain embodiments, the dome shaped support element 305 has a cover 308 located on top of the dome shaped support element 305 preferably comprised of Ethylene Vinyl Acetate (“EVA”) or other suitable material. Thermoplastic Elastomer gel or Polyurethane (“PU”) could also be used for the cushioning cover 308 on the dome shaped support element. This material provides additional cushioning properties to the dome shaped support element and also may be used to secure the dome shaped support element in its location. The cover 308 may be a less viscous material that is encapsulated or a thicker material that is not encapsulated. A non-encapsulated gel is preferable since it has less opportunity for rupture or breakage. The cover 308 is located on top of the dome shaped support element 305 inside of the heel 304 of the shoe. In addition, the cover 308 can take a variety of shapes including a shape similar to the dome shaped support element or any other shape.

Certain embodiments of the outsole and heel assembly are depicted in FIG. 5. The dome shaped support element 305 is located on top of the viewing window 303. A substance such as a liquid, gel, or compressed air may be placed inside the dome 507 to provide additional support. The feet 203 of the dome fit within the heel section and may be used to secure the dome shaped support element in place in conjunction with the cover 308 and viewing window 303. The viewing window may be composed of thermoplastic elastomer or thermoplastic polyurethane. The dome shaped support element 305 is covered with the cushioning cover 308 as described above. There is space surrounding the dome in the heel 506 may be filled with a gas, soft solid material, aqueous solution, or gel. The dome cover could also be molded to fill the space 506. On top of the outsole assembly in the heel portion there may be a plate 504. This plate can be composed of fiberglass, Kevlar®, thermoplastic rubber, or any other material that would be recognized by one of ordinary skill in the art to be a suitable material. An example of a suitable material is Acrylonitrile Butadiene Styrene (“ABS”) plastic.

The dome shaped support element 305 in the heel portion is not inflexible. While the material comprising the dome shaped support element 305 has similar properties to Delrin®, when pressure is applied such as standing or walking, the dome shaped support element 305 structure can expand the footprint of the dome structure in order to cushion the foot. The cover 308 would expand in turn with the expansion of the dome shaped support element 305 and provide additional cushioning properties to the impact. The heel plate, 504 distributes the compression evenly on the dome shaped support element and provides additional stability to the assembly. The heel plate 504 may be solid or alternatively have an opening to allow the cover 308 to support the foot more directly under the insole.

FIG. 6 depicts the bottom view of the assembled shoe bottom. The viewing window allows an individual to see the bottom of the dome as depicted in FIG. 4.

FIG. 7 depicts certain embodiments of the bottom assembly 701 of the shoe. The dome shaped support element 305 is fitted on top of viewing window 303. Thermoplastic Elastomer gel insert 308 is placed on top of the dome to secure the dome. A heel plate 504 is placed on top of the gel insert and may be solid or have an opening as shown in FIG. 7. The heel plate may be composed of tuck board. An insole 706 is then inserted on top of the bottom assembly.

FIG. 8 depicts certain embodiments of a completed article of footwear incorporating certain embodiments of the invention claimed herein.

It should be understood that the described embodiments have been disclosed by way of example, and that other modifications may occur to those skilled in the art without departing from the scope and spirit of the appended claims. 

1. An article of footwear comprising: an upper extending around at least a portion of a foot; an outsole secured to the upper; a midsole detachably secured to the outsole wherein the heel portion of the midsole comprises a vertically projecting generally dome shaped support element, the generally dome shaped support element located within a portion of the outsole where the dome shaped support element is in contact with outsole interior sidewalls, while in an uncompressed state said dome shaped support element being at least partially covered by a cushioning cover comprised of a material less stiff than the material comprising the dome shaped support element.
 2. The article of claim 1 wherein the dome shaped support element comprises a series of legs projecting from the apex of the dome towards the outsole.
 3. The article of claim 2 wherein the legs are generally triangular in shape.
 4. The article of claim 3 wherein the legs have small projections that extend from the legs generally perpendicular to the legs at the point of contact with the outsole.
 5. The article of claim 1 wherein the cushioning cover is dome shaped.
 6. The article of claim 1 wherein the cushioning cover is generally rectangular shaped.
 7. The article of claim 1 wherein the cushioning cover has vents.
 8. The article of claim 1 wherein the cushioning cover is partially in contact with a heel plate.
 9. The article of claim 1 wherein the cavity surrounding the dome shaped support element comprises a gas.
 10. The article of claim 1 wherein the cavity surrounding the dome shaped support element comprises an aqueous solution.
 11. The article of claim 1 wherein the cavity surrounding the dome shaped support element comprises a gel.
 12. An article of footwear comprising: an upper extending around at least a portion of a foot; an outsole secured to the upper; a midsole detachably secured to the outsole wherein the heel portion of the midsole comprises a vertically projecting generally dome shaped support element, the generally dome shaped support element located within a portion of the outsole where the dome shaped support element is in contact with outsole interior sidewalls only while in an compressed state and being at least partially covered by a cushioning cover comprised of a material less stiff than the material comprising the dome shaped support element.
 13. The article of claim 12 wherein the dome shaped support element comprises a series of legs projecting from the apex of the dome towards the outsole.
 14. The article of claim 13 wherein the legs are generally triangular in shape.
 15. The article of claim 14 wherein the legs have small projections that extend from the legs generally perpendicular to the legs at the point of contact with the outsole.
 16. The article of claim 12 wherein the cushioning cover is dome shaped.
 17. The article of claim 12 wherein the cushioning cover is generally rectangular shaped.
 18. The article of claim 12 wherein the cushioning cover has vents.
 19. The article of claim 12 wherein the cushioning cover is partially in contact with a heel plate.
 20. The article of claim 12 wherein the cavity surrounding the dome shaped support element comprises a gas.
 21. The article of claim 12 wherein the cavity surrounding the dome shaped support element comprises an aqueous solution.
 22. The article of claim 12 wherein the cavity surrounding the dome shaped support element comprises a gel.
 23. An article of footwear comprising: an upper extending around at least a portion of a foot; an outsole secured to the upper; a midsole detachably secured to the outsole wherein the heel portion of the midsole comprises a vertically projecting generally dome shaped support element, the generally dome shaped support element located within a portion of the outsole where the dome shaped support element is in contact with outsole interior sidewalls while in an uncompressed state and being at least partially covered by a cushioning cover comprised of a material less stiff than the material comprising the dome shaped support element; the cushioning cover partially covered by a heel plate; and the heel plate extends at least partially from the heel of the shoe towards the toe of the shoe.
 24. The article of claim 23 wherein the dome shaped support element comprises a series of legs projecting from the apex of the dome towards the outsole.
 25. The article of claim 24 wherein the legs are generally triangular in shape.
 26. The article of claim 25 wherein the legs have small projections that extend from the legs generally perpendicular to the legs at the point of contact with the outsole.
 27. The article of claim 23 wherein the cushioning cover is dome shaped.
 28. The article of claim 23 wherein the cushioning cover is generally rectangular shaped.
 29. The article of claim 23 wherein the cushioning cover has vents.
 30. The article of claim 23 wherein the cavity surrounding the dome shaped support element comprises a gas.
 31. The article of claim 23 wherein the cavity surrounding the dome shaped support element comprises an aqueous solution.
 32. The article of claim 23 wherein the cavity surrounding the dome shaped support element comprises a gel.
 33. An article of footwear comprising: an upper extending around at least a portion of a foot; an outsole secured to the upper; a midsole detachably secured to the outsole wherein the heel portion of the midsole comprises a vertically projecting generally dome shaped support element, the generally dome shaped support element located within a portion of the outsole where the dome shaped support element is in contact with outsole interior sidewalls only while in an compressed state and being at least partially covered by a cushioning cover comprised of a material less stiff than the material comprising the dome shaped support element; the cushioning cover partially covered by a heel plate; and the heel plate extends at least partially from the heel of the shoe towards the toe of the shoe.
 34. The article of claim 33 wherein the dome shaped support element comprises a series of legs projecting from the apex of the dome towards the outsole.
 35. The article of claim 34 wherein the legs are generally triangular in shape.
 36. The article of claim 35 wherein the legs have small projections that extend from the legs generally perpendicular to the legs at the point of contact with the outsole.
 37. The article of claim 33 wherein the cushioning cover is dome shaped.
 38. The article of claim 33 wherein the cushioning cover is generally rectangular shaped.
 39. The article of claim 33 wherein the cushioning cover has vents.
 40. The article of claim 33 wherein the cavity surrounding the dome shaped support element comprises a gas.
 41. The article of claim 33 wherein the cavity surrounding the dome shaped support element comprises an aqueous solution.
 42. The article of claim 33 wherein the cavity surrounding the dome shaped support element comprises a gel. 